*{
    margin:0;
    padding:0;
    box-sizing: border-box;
}
.clearfix:after,
.clearfix:before{
    content: "";
    display: table;
    clear: both;
}
.tb{
    width:500px;
    margin:300px auto;
}
li{
    list-style-type: none;
}
a{
    text-decoration: none;
}
.tb .nav li{
    float:left;
}
.nav li{
    width:80px;
    height:40px;
    text-align: center;
}
.nav li a{
    color:#3c3c3c;
    font-size: 13px;
}
.nav .active a{
    padding-bottom:6px;
    color:#ff4400;
    font-weight: bold;
    border-bottom:2px solid #ff4400;
}
.nav .active:hover a{
    padding-bottom:6px;
    color:#ff4400;
    font-weight: bold;
}
.main > div{
    display: none;
}
.main > div.active{
    display: block;
}
.main > div ul{
    float:left;
    padding-left:36px;
}
.main > div ul a{
    font-size: 13px;
}
.main > div ul a{
    color:#3c3c3c;
    font-size: 13px;
}
.main > div ul .li-1 a{
    color:#ff5000;
}
.main > div ul .li-2 a:hover{
    color:#ff5000;
}
